/Engine/Source/Editor/UnrealEd/Public/Subsystems/EditorAssetSubsystem.h
Checkout all assets in a directory. It will load the assets if needed. All objects that are in the directory will be checked out. Assets will be loaded before being checked out.
True if the operation succeeds.
bool CheckoutDirectory ( const [FString](API\Runtime\Core\Containers\FString) & DirectoryPath, bool bRecursive )